Methoni's Castle
The beautiful Venetian Castle of Methoni, built literally on the sea, is among the most beautiful monuments of the area.
Typical example of a castle/state,it extends to a long stretch of coastline and that's the reason why touring inside takes quite some time,while necessary if you want to reach the narrow stone bridge which connects the castle with the fortified islet ( built in the sea) of Bourtzi.
In fact, it was so well fortified, that even after the end of the revolution the Greeks could not Conquer it until the Ottoman guard handed it over to the French.
So if you only have time to visit a castle in the area, that's indeed the one !